Yemen's interior ministry said 55 al-Qaeda militants were killed in an hours-long series of strikes on a training camp operated by the group in the country's south.
The ministry said three senior members were among those killed, without elaborating. It said the identification process for those killed was continuing.
The operation, which started on Sunday and is believed to have involved US drones, targeted a sprawling training camp in the rugged mountains of Mahfad between Abyan, Shabwa and al-Bayda provinces.
Security officials said the camp's infrastructure was destroyed. Washington considers Yemen's al-Qaeda branch to be the most active in the world.
Three more al-Qaeda suspects, including an alleged senior militant, were killed yesterday in a drone strike in southern Yemen, a local official said.
The attack was the latest in an intensified air campaign that began days after the jihadist network's Yemen affiliate vowed to fight Western "crusaders".
The US is the only country operating with drones over Yemen. Its officials rarely acknowledge the covert drone programme.
The Yemeni official, requesting anonymity, said that shortly after midnight a drone fired a missile at an off-road vehicle carrying three men in the southern Shabwa province, seen as a stronghold for al-Qaeda in the Arabian Peninsula (AQAP).
Witnesses confirmed that the vehicle had been destroyed and said they saw the charred remains of three individuals. They said an unmarked helicopter arrived shortly after the strike to retrieve the bodies.
"The operation seems to indicate that one of the dead could be an important leader of al-Qaeda," one witness said.
The attacks came less than a week after AQAP chief Nasser al-Wuhayshi pledged in a rare video to fight "crusaders" worldwide.
AQAP is seen as one of the most sophisticated affiliates of the global terror network.